This invention relates to electrical power management systems and, more particularly, to power management systems for computers.
The widespread use of large-scale computers in critical applications which demand uninterrupted program execution has led to the development of uninterruptable power sources, commonly referred to as UPS. Generally, a UPS is in the form of a solid state inverter which converts a source of stored electrical energy into alternating current power having the same frequency and voltage as the power normally supplied to the computer from utility operated power mains. The stored energy source is generally a bank of batteries which is kept charged by charger circuits powered from the mains. In the event of an interruption of utility power, the UPS automatically provides power to the computer for a maximum duration determined by the capacity of the battery bank.
In order to ensure uninterrupted operation of computers for the maximum anticipated duration of power outage, very large and expensive UPS systems are employed in conjunction with large banks of batteries.
Recently, the widespread availability of microprocessors has resulted in a proliferation of low cost microcomputers as well as small and medium scale computers. These computers have found varied uses in business offices and manufacturing plants for such applications as word and data processing and data base management. In other applications, a microcomputer may be used as a remote input terminal to furnish data to a large scale computer. It will be appreciated that in this latter application, an interruption in power to the microcomputer can result in data loss to the large-scale computer even though that large-scale computer is protected against power interruptions. Further, routine power interruptions in a business office environment often result in unpredictable data loss in word processing and data management applications. Voltage transients and high frequency noise on the power lines can also cause loss of data or other erratic behavior in the computers.
From the above discussion, it may be seen that an uninterruptable power source for micro, small, and medium size computers is highly desirable. However, the large and expensive UPS systems developed for large scale computers are not economically feasible for use with smaller and lower cost computers. The physical distribution of multiple microcomputers throughout a large facility further complicates the task of providing uninterruptable power.
Accordingly, it is an object of the present invention to provide a new and improved computer power management system.
It is another object of the present invention to provide a new and improved computer power management system controlled by a microprocessor.
It is yet another object of the present invention to minimize the amount of uninterruptable power needed to operate one or more computers, by using a power management system which communicates with each computer being powered to provide power system status and command data via an input data port of the computer.
It is yet another object of the present invention to minimize the amount of uninterruptable power needed to operate one or more computers by using a power management system which communicates with the computer being powered both to provide power system status and command data and to receive computer system status and command data via an input/output data port of the computer.